Apparatus for checking geometrical features of pieces with rotational symmetry

ABSTRACT

An apparatus is disclosed for checking the geometric characteristics of mechanical objects having rotational symmetry, such as shafts or bushings. A longitudinal support element defines a longitudinal axis and first reference surfaces, at least one modular coupling element is removably coupled to, and is adjustable longitudinally along, the longitudinal support element and provides second reference surfaces which cooperate with the first reference surfaces to align a linear guide portion transversely of the longitudinal axis. A fastener secures the modular coupling element, which removably supports a gauging device, to the longitudinal support element and a locking/unlocking device cooperates with the gauging device and guide portion for locking the gauging device to the modular coupling element.

TECHNICAL FIELD

The present invention relates to an apparatus for checking dimensions ofa mechanical piece with rotational symmetry, comprising longitudinalsupport means with at least one elongate element defining a longitudinalaxis and first reference surfaces, support devices with modular couplingelements, removably coupled to the longitudinal support means inlongitudinally adjustable locations, and defining linear guide portions,and second reference surfaces for cooperating with the first referencesurfaces and aligning the guide portions along mutually paralleldirections, transversal with respect to the longitudinal axis, fasteningmeans including fastening devices to secure said modular elements to thelongitudinal support means, and at least one gauging device.

BACKGROUND ART

In order to check in a substantially simultaneous way a plurality ofdimensions and/or other geometrical features of mechanical pieces withrotational symmetry as, for example, shafts or bushings, after themachining operation on a machine tool, it is known to use apparatusescomprising a support base bearing a structure with elements forsupporting--with an appropriate orientation--the piece to be checked andgauging devices, suitably positioned so as to touch portions of thepiece for performing the required checkings.

Such an apparatus, or bench, is described, for example, in theInternational application published under No. WO-A-8904456. This benchhas a support structure with four prismatic bars that define, insubstance, a reference plane and two longitudinal openings, for enablingthe fastening of V-shaped elements carrying the piece, by means of twobolts that determine the arrangement of the same V-shaped elements onthe bars.

Gauges for checking diametral dimensions of the piece are carried byfurther support elements that include movable prismatic bars and defineopenings housing fastening means.

The bench described in application No. WO-A-8904456 has a rugged andinexpensive structure and the V-shaped support elements, the gauges andthe other elements that form the bench, and relevant connections to thesupport structure, enable a high degree of accuracy and guaranteeremarkable modularity and flexibility of use.

DISCLOSURE OF INVENTION

An object of the present invention is to provide an apparatus forchecking geometrical characteristics of mechanical pieces withrotational symmetry, like shafts or bushings, having a simple, ruggedand modular structure like that of the bench described in theInternational application No. WO-A-8904456, providing an even greaterflexibility of use, by employing a limited number of components andaccomplishing rapid and simple operations as the morphologicalcharacteristics of the piece to be checked vary, and guaranteeing a veryhigh degree of accuracy.

This and other objects are attained by an apparatus according to theinvention, wherein the elongate element lies in a substantially centralposition with respect to each linear guide portion, and the fasteningmeans include a single fastening device for each modular element, thegauging device being coupled, adjustably along a trasversal direction,to the guide portion of at least one modular element. An importantresult attained by the present invention consists in the extensivepossibility of adjusting the various components and the simplicity andthe rapidity required for performing these adjustments.

Among the advantages offered by the invention there is the possibilityof assembling the apparatus according to various configurations, bydisposing of a limited number of components.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is hereinafter described in detail with reference to theenclosed sheets of drawings, given by way of non-limiting example,wherein

FIG. 1 is a schematic perspective view showing some components of theapparatus according to the invention,

FIG. 2 is a lateral view of an apparatus according to a first embodimentof the invention,

FIG. 3 is a cross-sectional view of the apparatus shown in FIG. 2, alongline III--III of FIG. 2, with some parts omitted and others furthercross-sectioned for reasons of simplicity and clarity,

FIG. 4 is a cross-sectional view of the apparatus of FIG. 2, along lineIV--IV of FIG. 2, with some parts omitted and others furthercross-sectioned for reasons of simplicity and clarity,

FIG. 5 is a partly cut-away longitudinal sectional view of the apparatusshown in FIG. 4, along line V--V of FIG. 4,

FIG. 6 is a lateral view of a part of the apparatus of FIG. 4,

FIG. 7 is a cross-sectional view of the apparatus shown in FIG. 2, alongline VII--VII of FIG. 2, with some parts omitted and others furthercross-sectioned for reasons of simplicity and clarity,

FIG. 8 is a cross-sectional view of a component of the apparatus shownin FIG. 2, along line VIII--VIII of FIG. 7,

FIG. 9 is a cross-sectional view of a component of FIG. 2, along lineIX--IX of FIG. 7,

FIG. 10 is a cross-sectional view of an apparatus similar to the oneshown in FIGS. 1 and 2, comprising a different component,

FIG. 11 is a lateral view, with some parts shown cross-sectioned, of anapparatus according to another embodiment of the invention,

FIG. 12 is a cross-sectional view of the apparatus shown in FIG. 11,along line XII--XII of FIG. 11, with some parts not shown and othersfurther cross-sectioned for reasons of simplicity and clarity,

FIG. 13 is a partial cross-sectional view of an apparatus according to afurther embodiment, and

FIG. 14 is a cross-sectional view of a detail of the apparatus shown inFIG. 13, along line XIV--XIV of FIG. 13.

BEST MODE FOR CARRYING OUT THE INVENTION

The apparatus, or bench, shown in FIGS. 1-9 comprises support means withtwo elongate elements or cylindrical bars 1 and 2, having identicaldimensions, that define first reference surfaces and are arranged oneupon the other with parallel longitudinal axes lying in a same plane,for example a vertical plane, and transversal holding elements 3 and 4to which the ends of both bars 1, 2 are fixed.

Support devices comprise modular coupling elements 5 secured to the bars1, 2 by means of fastening means, i.e. each element 5 is fixed by meansof an associated fastening device with a bolt 6.

Different modular elements 5 have a substantially L-shape and the samethickness, and define upper linear guide portions 7, lower, planeresting surfaces 8 with relevant plane recesses 9, lateral, plane,resting surfaces 10, perpendicular to the lower surface 8, and throughholes 11 with axes substantially parallel to the linear guide portion 7.Each linear guide portion 7 defines, for example, an associated guideopening, as shown in FIGS. 1, 3 and 4, but may comprise portions havinga different shape (see FIGS. 13 and 14, and, hereinafter, the relevantdescription). The arrangements of the modular elements 5, substantiallyon transversal planes, are defined by the contact between the firstreference surfaces of bars 1, 2 and the relevant resting surfaces 10 and8, the latter in correspondence with the recess 9, that form secondreference surfaces. The arrangement of the bars 1, 2 and the restingsurfaces 8 and 10, guarantees the alignment of the relevant guideportions 7 along mutually parallel, transversal directions. In such anarrangement, the plane in which the longitudinal axes of the bars 1, 2lie, substantially represents a midplane for the linear guide portions7. The arrangement is secured by means of bolts 6, that comprise screws12 and nuts 13, the first (12) housed in the holes 11 and between thebars 1, 2, the second (13) clamped to the bars 1, 2 in positionsopposite to the resting surfaces 10.

Two limiting elements 14, 15 are also secured to the cylindrical bars 1,2,--as shown in FIG. 2--by means of bolts 6, in order to determine theposition of a piece 20 to be checked, for example a shaft defining alongitudinal symmetry axis, along a longitudinal direction.

Further support devices and checking means are fastened to the modularcoupling elements 5, adjustably coupled to the relevant guide portions7.

FIG. 3 shows, in particular, a V-shaped support device 21. Two of thesedevices 21, illustrated in the bench of FIG. 2, support the shaft 20 tobe checked and define the rest position of its longitudinal axis. Device21 comprises two base elements 22, 23 with feathers 24 housed in theopening of the linear guide 7 of the associated coupling element 5, andtwo bearing members 25, 26 that define a V-shaped support seat for shaft20. An adjustment shaft 27 is supported by a central element 28, clampedto the coupling element 5, freely rotatable about its axis. Shaft 27 ispositioned in a transversal, horizontal direction, parallel to the guideportion 7, and has ends with right and left threads coupled toassociated threaded holes of the base elements 22, 23: the rotation ofshaft 27, set in motion, for example, at an end protruding from one ofthe elements 22, 23, causes displacements of elements 22, 23, towardsand away from each other, so as to adjust the reciprocal transversalposition of the relevant members 25, 26 as the nominal dimensions ofpiece 20 to be checked vary.

Adjustable reference limit stops 29, 30 are clamped to the members 25,26, by means of screws 31, 32, thereby permitting rotationaldisplacements of the limit stops for their positioning in a centeringposition, as shown in FIG. 3 for limit stop 29. Limit stops 29, 30 (orat least one of them) are positioned in said centering position whenadjusting the reciprocal transversal position of the members 25, 26, byoperating--in the previously described manner--on shaft 27: the correctpositioning is obtained when contact occurs between the piece 20,resting on the V-shaped seat defined by members 25, 26, and limit stops29, 30. Limit stops 29, 30 allow the axis of the piece 20 to bemaintained in alignment on the same longitudinal direction, as thenominal diametral dimensions of the latter vary.

Consequently, the transversal checking position is univocally defined.

Once the transversal position of the bearing members 25, 26 is defined,this position is held by locking each of the base elements 22, 23 to thecoupling element 5, by means of a rapid locking/unlocking device 33,schematically shown in the drawings for element 22 only. The device 33comprises an anchor element 34 housed in guide portion 7, coupled to anend of a lever 35 that is pivotably coupled, at an opposite end, to acam 36 housed in an opening 37 of element 22, and in contact withsuitably shaped surfaces of opening 37. A pin 38 is coupled, by means ofa threaded coupling, to a hole of element 22, and has a tapered end forcontacting an oblique surface of cam 36, as shown in the drawing. Theurging of pin 38 towards cam 36 and the contacting of portions of cam 36with the shaped surfaces of opening 37, cause rotary displacements ofcam 36, and the consequent lifting of the anchor element 34, that is inturn urged against surfaces of the guide portion 7, thus accomplishingthe locking action.

FIG. 4 shows a modular element 5, identical to the one shown in FIG. 3,that carries checking means for checking diametral dimensions of shaft20.

Such checking means comprise two identical gauging devices 40,adjustably coupled, in a specular arrangement, to the linear guideportion 7 of element 5. Each device 40 comprises a substantiallyintegral member with a base portion 41 with feathers 42 housed in theopening of portion 7, and a rapid locking/unlocking device identical tothe one (33) previously described and of which just the opening 37 isshown in FIG. 4. The base portion 41 comprises a fixed, reference part43, that carries the feathers 42, a part 44 with reduced thicknessdefining fulcrum means, and a relevant rotation axis, and a movableelement, or arm, 45, that can perform limited rotational displacementsabout the rotation axis, by virtue of the deformations of the part 44with reduced thickness. The arm 45 defines, at a free end, three seats46 (FIG. 5), substantially parallel to one another along transversaldirections, and a feeler 47 is coupled to one of the three seats 46. Afirst through hole 48 and a second through hole 49, having axes parallelto the guide portion 7, are defined in the fixed part 43 of base portion41.

A detecting device comprises an axial movement gauging head 50 insertedin the first though hole 48 and clamped by fastening means comprising aclamping bracket 51. The head, of a known type, comprises an axiallymovable stem 52, that contacts the free end of arm 45, at the oppositeside with respect to feeler 47, aligned with the latter along atransversal direction, and transducer means (not shown in the drawing)adapted to provide electrical signals indicative of the axial positionof movable stem 52. Processing and display means, schematically shownand identified by reference number 53 in FIG. 2, are electricallycoupled, by means of electric cables 54, in a way not shown in thefigure, to the transducers of heads 50 of both the gauging devices 40for processing said signals and providing indications regarding thediametral dimension to be checked.

The clamping bracket 51 (which is also shown in FIG. 6) comprises aplate 55, bent to the shape of a U, with two through holes 56, at thelegs of the U, substantially aligned with the first through hole 48. Thehead 50 is inserted in holes 56. A clamping screw 57 is coupled to athreaded hole 58 of plate 55, at the base of the U, and has an endcontacting an area of base portion 41. The contour of each of thethrough holes 56 has a generally circular shape, with two slantinglinear portions 59 that, further to the clamping of screw 57, contactthe lateral surface of head 50 substantially at two points. In this wayhead 50 is clamped with particular accuracy and safety in a positiondefined by said two points and by the contact area between the lateralsurface of the head and a limited surface portion of hole 48, oppositeto the slanting portions 59.

A rapid zero-setting device 60 has a substantially elongate, cylindricalshape, is partially housed in the second through hole 49 of fixed part43, and comprises: a knob 61, at a first end, defining first and secondlimit stop surfaces 62 and 63, a circular flange 64 that defines a thirdlimit stop surface 65, a portion with smaller diameter 66, at a secondend, that is housed in a through hole 67 of arm 45 and defines a fourthlimit stop surface 68, and a compression spring 69, arranged between asurface portion of the fixed part 43 and the first limit stop surface62. The rapid zero-setting device 60 enables a rapid adjustment of thetransversal position of the gauging device 40 in the relevant linearguide portion 7 before clamping the gauging heads 50, as describedhereinafter.

The checking means comprise supplementary gauging devices 70 forchecking longitudinal dimensions of shaft 20.

FIGS. 7, 8 and 9 show one of said supplementary devices 70, thatcomprises: a base support 71, coupled to the guide portion 7 of one ofthe coupling elements 5, in an adjustable way as that of the previouslydescribed components, a reference part, or frame 72, supported by basesupport 71 with an orientation adjustable about a vertical geometricaxis, and a movable arm 73, pivotably coupled to frame 72 for performingpivotal movements about an axis lying in a transversal plane, inparticular a vertical rotation axis. A coupling pin 74, fixed withrespect to frame 72, is partially housed in a seat of the base support71 and defines the above mentioned vertical geometric axis, and aclamping bracket 75, similar to bracket 51 shown in FIGS. 4 and 6,clamps the pin 74 to secure the frame 72 to the support 71.

Fulcrum means defining said vertical rotation axis for arm 73 comprise apair of laminar portions 76, coupled both to the frame 72 and to aflange 77 integral with arm 73.

A feeler 78 is coupled to a free end of arm 73. Transmission means, atthe opposite end of the movable arm 73, comprise three substantiallyplane surface portions 79, 80 and 81, sloping with respect to saidtransversal plane, i.e. to the plane of FIG. 7, and each of three thoughholes 82, 83 and 84, defined in the frame 72, faces a corresponding oneof such sloping surface portions 79, 80, 81.

A detecting head, entirely similar to heads 50 shown in FIG. 4,comprises an axial movement gauging head 85 including a movablecontacting stem 86. The head 85 is coupled to frame 72 by means of aflange 87 and a bracket 88, and is arranged substantially on saidtransversal plane, in particular along a vertical direction, in such away that the movable stem 86 is partially housed in through hole 83 andfaces the sloping portion 80. Transmission means also comprise an idleelement, in particular a ball 89, positioned between movable stem 86 andsloping portion 80, in contact with both, in order to enabledisplacements of the former (86) along said vertical direction, as aconsequence of pivotal movements of arm 73. The ball 89 is kept in theformerly mentioned arrangement by means of a wall of the frame 72 and ofsuitable rims defined by each of the sloping surface portions 79, 80 and81, partially shown in the FIGS. 7, 8 and 9 and indicated by referencenumber 90.

A zero-setting device 91 is housed in hole 84 defined by frame 72 andcomprises a stem 92 with an adjustment knob 93, coupled, by means of athreaded coupling, to a coupling element 94 fixed to the frame 72. Arounded-off end of the stem 92 faces the sloping surface area 81, whilelimit stop surfaces of knob 93 define a zero-setting configuration ofdevice 91.

The operation of the apparatus shown in FIGS. 1-9 is the following.

The various components of the apparatus are, at first, roughlypositioned, both longitudinally and transversally, so as to enable theintroduction between the limiting elements 14, 15 and the support on theV-shaped devices 21 of a standard part or "master" 20 that has thenominal dimensions of the shafts to be checked. The limiting elements14, 15 are, thereafter, abutted against the ends of the master 20 andsecured to the bars 1, 2 in order to define the longitudinal position ofthe master 20.

For the correct transversal positioning of the axis of master 20, it isnecessary to adjust each V-shaped support device 21 by arranging limitstops 29, 30 in a centering position and bringing bearing members 25, 26near to each other, by rotating shaft 27 until limit stops 29, 30contact the surface of master 20.

The checking means are positioned--at first--along the longitudinaldirection of the apparatus, by adjusting and securing, by means of bolts6, the position of the associated coupling elements 5 on cylindricalbars 1, 2, so as to bring the feelers 47 in correspondence with thediametral sections to be checked, and the feeler 78 (also by virtue of atransversal adjustment of its associated gauging device 70 along therelevant guide portion 7) in correspondence with a transversal shouldersurface 20a of the master 20, the relative longitudinal position ofwhich is to be checked. In said first step the gauging heads 50, 85 arenot coupled to the associated gauging devices 40, 70.

The gauging devices 40 (FIG. 4) are brought towards the piece (master)20, through displacements along the guide portion 7 of the associatedcoupling element 5, by operating simultaneously the knobs 61 of therapid zero-setting devices 60 in order to abut the second limit stopsurfaces 63 against the fixed parts 43: when feelers 47 contact thesurface of piece 20, the displacements continue until arm 45 and thefourth limit stop surface 68 of each device 60 abut against each other,due to a limited deformation of the part 44 with reduced thickness, thusdefining a mechanical reference position of feeler 47. Thereafter, eachbase portion 41 is locked to element 5 by means of the associated rapidlocking/unlocking device 33, and the knobs 61 are released.

Thus, each zero-setting device 60 returns in a rest position that isdetermined by the thrust of the spring 69 and the abutment between thesurface 65 and the base portion 41.

Thereafter, the gauging heads 50 are inserted and axially displaced inthe associated holes 48 and thus their movable stems 52 are urged tocontact the arms 45 until there is detected, by means of the signalssent to the processing and display means 53, a "zero" condition of heads50: when this condition occurs, clamping is performed by means of theclamping bracket 51.

The arrangement of the limit stop surfaces 63 and 68 of the rapidzero-setting devices 60 is such that, when the above indicatedzero-setting operations have been carried out, a sufficient (and preset)pre-stroke for each arm 45 is guaranteed, i.e. contact between thefeelers 47 and pieces 20 having radial dimensions smaller than thenominal dimensions of an amount that does not exceed said pre-stroke isguaranteed.

Moreover, the rest positions of the zero-setting devices 60, defined bythe limit stop surfaces 65, ensure a sufficient extra-stroke for each ofarms 45, i.e. a sufficient amount of space between arms 45 and surfaces68 so as to enable the feelers 47 to freely displace when contacting apiece 20 whose radial dimension is larger than the nominal one.

With regard to the gauging device 70, once the longitudinal andtransversal positions are roughly adjusted and the associated couplingelement 5 has been secured to bars 1, 2 and the base support 71 has beenlocked to the guide portion 7 of element 5 itself, the positioning ofthe frame 72 is adjusted with respect to the base support 71 byreleasing the clamping bracket 75 from pin 74 and causing a rotation ofthe frame 72 about the vertical geometric axis in such a way as to urgefeeler 78 against the transversal surface 20a. In the course of thisrotation, the reciprocal position existing between the arm 73 and theframe 72 is held--in correspondence with a partial deflection of thelaminar portions 76-- in a rotation sense by virtue of the contactoccurring between the sloping surface portion 81 and the end of the stem92, in the zero-setting configuration of device 91, and in the oppositerotation sense by thrusting--by hand or by means of a suitable,removable, mechanical limit stop not shown in the drawings--the arm 73and the feeler 78 towards the surface 20a of the master 20. When contactwith this surface 20a occurs, the frame 72 is clamped, by means ofbracket 75, and the thrust applied to the arm 73 is released; the end ofthe stem 92 is brought away from the surface portion 81, by operating onthe knob 93. Thereafter, the ball 89 is displaced so as to contact thesurface portion 80, and the head 85 is clamped to flange 87, by means ofbracket 88, as shown in FIG. 7, in correspondence with a zero conditionof the head 85 itself detected by means of the processing and displaymeans 53. The subsequent removal of the master 20 causes arm 73 toreturn to a mechanical rest position that guarantees a pre-stroke and anextra-stroke of the arm 73, that are defined by the zero-settingconfiguration of device 91.

The arrangement of the sloping surface portions 79, 80, 81 and theassociated holes 82, 83, 84 enables the clamping of the gauging head 85by means of flange 87 and bracket 88, with the interpositoning of theball 89, at any of the surface portions 79, 80, 81, as the spaceavailable for the specific application varies. In an entirely identicalway there can be changed the position of the zero-setting device 91,partially housed in the hole 82, or in the hole 83, by fixing thecoupling element 94 at one of these holes 82, 83.

Therefore, device 70, that enables to check longitudinal lineardimensions, has longitudinal overall dimensions particularly small. Thisis mainly due to the presence of the transmission means with one of thesloping portions 79, 80 or 81 and the ball 89, and to the arrangement ofthe axial movement gauging head 85 in a transversal plane, substantiallyperpendicular to the displacement direction of feeler 78 and parallel tothe transverse surface 20a of the piece 20, the arm 73 and the fulcrummeans 76 substantially lying in such transversal plane.

Owing to the presence of ball 89, that provides for the movements ofparts along two different directions, the motion of the arm 73 causesmotion of the movable stem 86 substantially free without lateralcomponents of forces with respect to the translation axis of stem 86, soguaranteeing the correct operation of the head 85 and of the entiredevice 70.

Moreover, the sloping of the surface portions 79, 80 and 81 is such thatmeasurement displacements of arm 73, i.e. displacements of the arm dueto the contact between the feeler 78 and the surface 20a, causemovements of the sloping portion 80 (or 79, or 81) away from the head85, and consequently outward displacements of stem 86, urged byresilient means, known and not shown in the figures, that are part ofhead 85. Thanks to this particular arrangement, and to the action of theball 89 placed between the sloping surface portion 80 and movable stem86, the friction between the movable parts has a negligible effect inthe correct operation of gauging device 70.

Once the adjustment operations have been completed, the master isremoved and replaced by a piece 20, the dimensions of which are checkedon the basis of the signals provided by the heads 50, 85 to theprocessing and display means 53.

FIG. 10 shows a different gauging device 100 that can be coupled to oneof the modular elements 5 of the bench shown in the previous figures andthat enables the checking of diametral dimensions to be performed byjust one gauging head, for example an axial movement gauging head 101.The gauging device 100 comprises a fixed, base part 102, directly lockedto portion 7 of the element 5 with a rapid locking/unlocking device 33,and an oscillating frame 103, joined to the fixed part 102 by means ofan integral element 104 with reduced thickness, that defines fulcrummeans and a longitudinal geometric axis of rotation. The oscillatingframe 103 comprises an integral member 105, entirely identical to thebase portion 41, shown in FIG. 4, and the components of which areidentified by the same reference numbers, and a reference part 106 witha fixed, adjustable, feeler 107. Limiting means 108 and thrust meanswith a spring 109 are coupled to the fixed part 102 and the referencepart 106 for defining the position and limiting the displacements of theoscillating frame 103 about the axis of rotation defined by the elementwith reduced thickness 104.

In the course of the adjustment step--performed with the master 20arranged on the V-shaped support devices 21 in the checkingposition--the position of the base part 102 is adjusted along the guideportion 7, to carry the feeler 47 to contact the surface of the master20, while acting on the knob 61 of the rapid zero-setting device 60, andsuch position is locked by means of the device 33. The transversalposition of the feeler 107 is then adjusted to contact the surface ofthe master 20, and the head 101 is clamped to the integral member 105 bymeans of the bracket 51, with an operation similar to the onehereinbefore described with reference to the devices 40 shown in FIG. 4.

The configuration of the integral element with reduced thickness 104provides a considerable strength to forces that tend to cause torsionsabout vertical axes, for example, as a consequence of the frictionbetween the feelers 107, 47 and the surface of piece 20: this provides aspecific guarantee that, upon the positioning of the piece 20 in thechecking position, the fixed feeler 107 and the movable feeler 47 touchthe surface of the piece 20 at diametrally opposite points, i.e. thecontact points are aligned along a direction that is exactlyperpendicular to the longitudinal axis of the piece 20.

In addition to what is shown and described hereinbefore, many differentdevices may be adjustably fastened to relevant modular elements 5, thelatter being secured, on their turn, to the bars 1 and 2 as describedabove. Among such different devices the following may be cited asnon-limiting examples: motorized actuation devices for causing therotation of piece 20, and performing checkings, for example, regardingthe roundness of piece 20; support devices for pieces 20 of a differentshape and dimensions with respect to the V-shaped devices 21, including,for example, bearing centers; different checking means with contact orcontactless measuring heads, etc.

FIG. 11 shows, as an example only, an apparatus, or bench, according toa different embodiment, specifically featured for checking internaldiametral dimensions of pieces 120 with rotational symmetry, asbushings.

The bench shown in FIG. 11 comprises support means identical to those ofFIGS. 1 and 2, with two cylindrical bars 1, 2 whereto modular couplingelements 5 are clamped by means of bolts 6.

Devices for supporting piece 120 comprise an adjustable support 110,coupled to bars 1, 2 by means of bolts 111, and including a horizontalsupport section 112, adjustable in height, that carries a centeringdevice 113 with four adjustable pins 114, only two being shown in FIG.11, for the positioning of the piece 120.

Checking means with gauging devices 115 for checking external diametraldimensions are shown, for the sake of simplicity, in a very schematicway, and comprise fixed frames 116, movable parts 117 with associatedfeelers that contact the external surface of the piece 120, couplingelements 118, for example of the known "parallelogram" type, forenabling substantially linear displacements of the parts 117 withrespect to the frames 116, and transducer means (not shown in thefigure) for detecting the position of the parts 117 with reference tothe relevant fixed frames 116. A processing and display unit 153 iselectrically connected to the transducer means of the gauging devices115. The checking means further comprise a gauging device 119 forchecking internal diameters, more detailedly shown in FIG. 12.

The gauging device 119 has a structure substantially similar to thedevice 100 of FIG. 10, and comprises a fixed base part 121, adjustablycoupled to the guide portion 7 of a coupling element 5 and locked bymeans of a rapid locking/unlocking device 33, and an oscillating frame122, joined to the fixed part 121 by means of an integral element 123with reduced thickness that defines a longitudinal geometric axis ofrotation. The oscillating frame 122 comprises an integral member 124 anda reference part 125, with a fixed adjustable feeler 126, rigidlycoupled to member 124. Limiting means 127 and balancing means with aspring 128 are coupled to the fixed part 121 and the reference part 125for defining the position and limiting the displacements of oscillatingframe 122 about the geometric axis defined by the element 123 withreduced thickness. Integral member 124 supports, in turn, a movable arm129 with a feeler 130 at one of its free ends, and comprises a secondintegral element 131 with reduced thickness that defines fulcrum meansand enables displacements of arm 129 with respect to reference part 125.A rapid zero-setting device 132 comprises a knob 133, resilient meansand limit stop surfaces and a structure and operation substantiallysimilar to the ones of the device 60 shown in FIGS. 4 and 10. Adetecting device comprising an axial movement gauging head 134 iscoupled to integral member 124, fixed with respect to reference part125, by means of a bracket 135, and includes a movable stem 136contacting a second free end of movable arm 129. Cables 137 electricallyconnect head 134 with the processing and display unit 153.

During the zero-setting operations carried out on a master 120, it isnecessary to actuate knob 133 in order to define, by means of thearrangement of the limit stop surfaces of the device 132, a position offeeler 130 corresponding to a determined deflection of integral element131 and bring feeler 130 into contact with the internal surface of piece120, by adjusting the position of fixed feeler 126 so as to bring it toointo contact with the same surface. After having released knob 133, thehead 134 is clamped by means of bracket 135, with movable stem 136contacting arm 129, in correspondence with a signal value indicating the"zero" condition detected by unit 153.

By removing the master 120, a position of mechanical rest of integralmember 124 (in particular of the element 131 with reduced thickness)defines an appropriate amount of pre-stroke for movable arm 129 andguarantees the contact of feelers 126, 130 with the surfaces of pieces120 to be checked.

The various components of the apparatus may have constructional featuresdifferent from the ones described with reference to FIGS. 1-12. Theclamping bracket 51, 75, 88, 135, or only some of them, may for examplebe replaced by known devices having the same functions.

The modular coupling elements and the locking/unlocking devices may alsohave different construction. FIGS. 13 and 14 schematically show amodular coupling element 5' comprising a linear guide portion 7' thathas not a guide opening, but a T-shaped profile, and a member--forexample a base element 22' of a V-shaped support device 21'--adapted tobe coupled to such guide portion 7'. It is to be noted that the supportdevice 21' is fully equivalent to the device 21 of FIG. 3, and that theonly constructional differences, that will be described hereinafter,relate to the elements providing for an adjustable coupling between baseelement 22' and guide portion 7'.

The lateral faces of the base element 22' (extending parallel totransversal planes) comprise closing L-shaped edges 24', 24", adapted todefine a seat for the T-shaped profile of guide portion 7'. The baseelement 22' defines a first through hole 37' extending parallel to guideportion 7', and a second through hole 37", perpendicular to the firstone 37' and communicating with it, both holes 37', 37" housing a rapidlocking/unlocking device 33'. In particular, the second hole 37" housesa friction shoe 34' with upper specular slanting surfaces, and the firsthole 37' houses two bias elements 36', 36", each having a lower slantingsurface touching one of the upper surfaces. An adjusting screw 38' ispartially housed in a through hole of the bias element 36' and has athreaded end coupled to a threaded hole of the bias element 36". Acompression spring 35' is interposed between the bias element 36', 36",urging such elements away from each other.

The base element 22' is coupled to the modular element 5' by means ofthe cooperation between the L-shaped edges 24', 24" and the T-shapedprofile of guide portion 7'. When adjusting the transversal position ofthe base element 22' along the guide portion 7', the bias elements 36',36" are kept away from one another, by operating adjusting screw 38',and thanks to the action of compression spring 35', so that the frictionshoe 34' may slide on the T-shaped profile. When base element 22' is tobe kept in position, screw 38' is turned to move the bias elements 36',36" towards each other against the action of compression spring 35', sobiasing, through the cooperation between the slanting surfaces, frictionshoe 34' downward. In such a way the position of base element 22' islocked.

The manufacturing and assembling simplicity of an inspection bench,according to the above description is evident, as well as theflexibility of use and the simplicity and the rapidity of the associatedretooling operations.

The easy and cheap machining and assembling operations allowing theproduction of the basic components (bars 1 and 2, and modular couplingelements 5 with resting surfaces 8-10 and linear guide portions 7) andthe construction of a bench ensure a high level of modularity of theapparatus by employing simple means and with limited costs.

Another important feature of the apparatus is the remarkable compactnessand modularity of the various components, having constant overalldimensions in a longitudinal direction, substantially defined by thethickness of modular elements 5, and the possibility of use even inthose cases wherein the space available for performing a large number ofcheckings is limited.

Furthermore, the adjustment operations of the various components can beperformed in an extremely simple way, thanks to the lateralaccessibility of the associated fastening means 6, 33, and thus are nothampered by the presence of the piece 20 (or 120) to be checked.

The axial movement gauging heads 50, 85, 101, 134 can be replaced, byperforming simple mechanical operations, with different detecting headsable to detect and provide indications on the position or thedisplacements of the movable feelers 47, 78, 130: as an example, dialgauges, or mechanical, or electromechanical gauges of a different typemay be employed.

The support means defining the longitudinal direction can also consistof a single elongate central element, instead of the two bars 1 and 2shown in the figures. This elongate element and the correspondingmodular coupling elements will have suitable chamfers, different restingand reference surfaces and elements for the radial clamping (in theplace of bolts 6) for fastening the modular elements and aligning therelevant guide portions in a way substantially similar to what has beendescribed hereinbefore.

Moreover, even though in the figures the longitudinal directions of thesupport means (1, 2), and the linear guide portions 7 are shown onhorizontal planes, different arrangement of the support means, supportdevices and checking means may be provided, for example arranging bars iand 2 vertically, and vertically supporting a shaft 20 by means ofsupport devices including centers, also connected to the guide portions7 of modular elements 5.

I claim:
 1. An apparatus for checking the dimensions of a mechanicalpiece having rotational symmetry, comprising:a longitudinal supportincluding at least one elongate element defining a longitudinal axis andfirst reference surfaces, support devices with at least one modularcoupling element, removably coupled to the longitudinal support in alongitudinally adjustable location, and defining: a linear guideportion, and second reference surfaces for cooperating with the firstreference surfaces and aligning the guide portion transversely of thelongitudinal axis, the first and second reference surfaces definingsubstantially transversally centered positions of the guide portion withrespect to the longitudinal axis, a fastening device cooperating withsaid modular element and said longitudinal support, said fasteningdevice being adapted to secure said modular coupling element to thelongitudinal support, at least one gauging device removably andadjustably coupled to the guide portion of said modular element, and arapid locking/unlocking device, cooperating with said gauging device andsaid guide portion for locking the gauging device to the modularcoupling element.
 2. An apparatus according to claim 1 furthercomprising a plurality of said modular coupling elements which areremovably coupled to said longitudinal support in longitudinallyadjustable locations, the respective linear guide portions of saidmodular coupling element being aligned along mutually paralleldirections.
 3. An apparatus according to claim 2, wherein the gaugingdevice comprises a substantially integral member, coupled to therespective said modular element, and a detecting head coupled to theintegral member, the integral member including a fixed part, a part withreduced thickness and a movable arm carrying a feeler for touching themechanical piece to be checked, the detecting head being connected tothe fixed part and cooperating with the movable arm for detectingdisplacements of the movable arm.
 4. An apparatus according to claim 3,wherein said gauging device further comprises a zero-setting device,coupled to said fixed part of the integral member and including at leasta spring and limit stop surfaces, the zero-setting device being adaptedto cooperate with said movable arm for defining a mechanical referenceposition of the feeler.
 5. An apparatus according to claim 4, whereinsaid zero-setting device has a substantially elongate cylindrical shape,said fixed part of the integral element defining a through hole housingsaid zero-setting device, at least one of said limit stop surfaces beingadapted to touch the movable arm for defining said mechanical referenceposition of the feeler.
 6. An apparatus according to claim 2, whereinsaid elongate element has a substantially cylindrical shape.
 7. Anapparatus according to claim 6, wherein the longitudinal supportcomprises two elongate elements of a substantially cylindrical shape,arranged mutually parallel on a substantially central position withrespect to the linear guide portions of said support devices.
 8. Anapparatus according to claim 7, wherein said fastening devices of saidsupport devices are arranged, for each modular element, along atransversal direction, and cooperate with said elongate elements tosecure in position the associated linear guide portion in one of saidmutually parallel directions.
 9. An apparatus according to claim 8,wherein said second reference surfaces comprise two plane restingsurfaces reciprocally perpendicular.
 10. An apparatus according to claim9, wherein the fastening devices comprise bolts passing through saidelongate elements.
 11. An apparatus according to claim 2, wherein thesupport devices comprise V-shaped devices connected to respectivemodular elements, and adjustably coupled to respective guide portions,for defining a checking position for the mechanical piece the apparatusfurther comprising rapid locking/unlocking devices for locking theV-shaped devices to the respective guide portions.
 12. An apparatusaccording to claim 11, wherein each of the V-shaped devices comprisesbearing members and adjustable reference limit stops coupled to thebearing members, and adapted to assume a centering position whenadjusting the transversal position of the bearing members on a mastermechanical piece.
 13. An apparatus according to claim 4, wherein thegauging device further comprises, a clamping bracket for clamping saiddetecting head to the integral member.
 14. An apparatus according toclaim 13, wherein the detecting head is an axial movement gauging head.15. An apparatus according to one of claims 3, 4, 13, and 14, whereinsaid gauging device comprises a fixed base part, clamped to the couplingelement, an integral element with reduced thickness coupled to the basepart, and an oscillating frame coupled to the element with reducedthickness for performing oscillations with respect to the base part, theframe comprising a reference part with a fixed adjustable feeler, saidfixed part of the integral member being rigidly coupled to the referencepart.
 16. An apparatus according to any one of claims 1, 2 and 6 to 10,for checking internal dimensions of a mechanical piece having a symmetryaxis, wherein the support devices comprise an adjustable supportincluding a horizontal support section and a centering device foraligning the symmetry axis along a predetermined vertical direction, andthereby defining the position of the mechanical piece.
 17. An apparatusfor checking longitudinal dimensions of a mechanical piece withrotational symmetry, comprisinga longitudinal support including at leastone elongate element defining a longitudinal axis and first referencesurfaces, support devices with modular coupling elements, removablycoupled to the longitudinal support in longitudinally adjustablelocations, and defining linear guide portions, and second referencesurfaces for cooperating with the first reference surfaces and aligningthe guide portions along mutually parallel directions, transversal withrespect to the longitudinal axis, the first and second referencesurfaces defining substantially transversally centered positions of theguide portions with respect to the longitudinal axis, fastening devicescooperating with said modular elements and said longitudinal support, asingle one of said fastening devices being adapted to secure one of saidmodular elements to the longitudinal support, at least one gaugingdevice and at least one further gauging device, each one of them beingremovably coupled adjustably along relevant transversal directions tothe guide portion of one of the modular elements, and rapidlocking/unlocking devices, cooperating with the gauging device, furthergauging device and guide portions for locking said gauging device andfurther gauging device to the modular coupling elements, wherein saidgauging device includes: a base support adjustably coupled to the guideportion of the coupling element, a frame coupled in an adjustable way tothe base support, a fulcrum element coupled to the frame and defining arotation axis lying in a transversal plane, a movable arm coupled to thefulcrum element, and pivotable, with respect to the frame, about saidrotation axis, at least one feeler coupled to a free end of the movablearm for contacting a transversal surface of the mechanical piece to bechecked, a detecting head for detecting displacements of the armcomprising a movable stem displaceable on said transversal plane, and atransmission mechanism transmitting displacements of the feeler to saidmovable stem, and comprising at least one substantially plane surfaceportion, integral with the movable arm, sloping with respect to saidtransversal plane.
 18. An apparatus according to claim 17, wherein themovable stem of said detecting head is movable along a linear directionof said transversal plane, and the transmission mechanism comprises aball (89) containing said movable stem and said at least one surfaceportion, for transmitting the displacement of the arm to the detectinghead.
 19. An apparatus according to claim 18, wherein said transversalplane is substantially perpendicular to the longitudinal axis, themovable arm substantially lying in the transversal plane.
 20. Anapparatus according to claim 19, wherein said transmission mechanismcomprises three sloping surface portions, integral with the movable arm,including said at least one surface portion.
 21. An apparatus accordingto claim 20, wherein said further gauging device comprises azero-setting device, coupled to the frame, and including a stem forcooperating with one of said sloping surface portions for defining amechanical reference position of the movable arm.
 22. An apparatusaccording to any one of claims 17 to 21, wherein said detecting head isan axial movement gauging head adjustably and removably coupled to theframe.
 23. An apparatus for checking geometric dimensions of amechanical piece defining a longitudinal symmetry axis, comprising alongitudinal support, at least one support device coupled to thelongitudinal support, and at least one gauging device coupled to said atleast one support device and including:a reference part, a movable arm,a fulcrum element allowing mutual displacements between the movable armand the reference part, and a detecting head fixed with respect to thereference part and including a movable stem adapted to contact themovable arm, wherein said fulcrum element defines a rotation axis lyingin a transversal plane, the movable arm being pivotable with respect tothe reference part about said rotation axis, and said movable stem ofthe detecting head being displaceable on said transversal plane, thegauging device further including a least one feeler coupled to a freeend of the movable arm for contacting a transversal shoulder surface ofthe mechanical piece to be checked, and a transmission mechanism fortransmitting displacements of the feeler to said movable stem, thetransmission mechanism comprising at least one substantially planesurface portion of the movable arm, sloping with respect to saidtransversal plane.
 24. An apparatus according to claim 23, wherein saidtransversal plane is substantially parallel to said shoulder surface ofthe piece, and the transmission mechanism comprises an idle elementcooperating with both the movable arm and the movable stem of thedetecting head.
 25. An apparatus according to claim 24, wherein saididle element is a ball adapted to contact both said substantially planesurface portion of the movable arm, and the movable stem of thedetecting head.
 26. An Apparatus according to claim 25, wherein themovable arm substantially lies in said traversal plane.
 27. An apparatusaccording to claim 26, wherein said transmission mechanism comprisesthree sloping surface portions including said at least one surfaceportion.
 28. An apparatus according to claim 27, wherein the gaugingdevice comprises a zero-setting device, coupled to the reference part,comprising a stem for cooperating with one of said sloping surfaceportions for defining a mechanical reference position of the movablearm.